1. Field of the Invention
This invention relates generally to heat sink assemblies used for dissipating heat produced by electronic components. More particularly, it relates to heat sink assemblies utilizing high efficiency heat pipes as the heat transfer device in place of relying on the heat conduction of a metal such as copper. Still more particularly, it relates to an improved air cooled heat sink assembly having a shaped configuration for providing proper alignment and thermal contact between the heat sink and the electronic component, wherein contact is achieved by use of a biasing mechanism. In particular, the invention includes a heat collector with a hemispherically shaped end adapted to mate with a hemispherical socket in a second heat collector mounted on the electronic component for providing alignment and increasing the heat transfer surface area.
2. State of the Prior Art
A significant problem with electronic circuit board components, including integrated circuits, is that they generate substantial heat. Since most of these components are sensitive to excessive heat, it is necessary to provide some means of cooling the components. This problem has increased as technology has been developed allowing the components to be made smaller in size. This means that more components generating the same amount of heat can be packed into a smaller space. It also means that the surface area through which the heat must be dissipated has decreased. Use of various types of heat sinks, including heat pipes, for cooling are well-known. Using heat pipes is significantly more efficient since they are capable of transferring up to one thousand times more energy than a solid copper bar.
The cooling systems presently being used have certain disadvantages. Some of the systems must be manufactured as an integral part of the printed circuit board assembly. As described in U.S. Pat. No. 4,019,098 to McCready et al, there is shown a heat pipe cooling system wherein one heat pipe for each row of integrated circuit packages is contained in a heat transfer structure. The heat transfer structure is secured to the circuit board and the integrated circuit packages are secured to the other side of the heat transfer structure. The disadvantage of this system is that it must be manufactured as a part of the printed circuit board assembly and is not readily separable from the printed circuit board or the components being cooled. Other systems utilize a liquid to cool the electronic components. Still others cool by refrigeration. In both cases these systems are costly and somewhat difficult to maintain. Some heat sinks are rigidly attached to the electronic component by solder or thermally conductive adhesive. These can, because of their weight, add excessive stress to the component and its attachment to its next level of assembly (PC board) especially during shipment or handling. Other heat sink cooling systems depend on placing the heat sink in contact with the electronic component through separable thermally conductive interfaces. The problem with these systems is that their effectiveness is reduced if their interfaces are misaligned or do not make proper contact. It is desirable to maximize the heat transfer across the interface, since the more heat which passes into the heat sink through the interface, the more efficient the heat sink. Uniform contact and proper alignment of the interfaces will maximize thermal conductivity at the interface, and thereby improve the overall efficiency of the heat sink.